Planetary gear transmission systems or components – Fluid drive or control of planetary gearing – Fluid resistance inhibits relative rotation
Patent
1995-01-03
1996-05-07
Wright, Dirk
Planetary gear transmission systems or components
Fluid drive or control of planetary gearing
Fluid resistance inhibits relative rotation
475262, F16H 4704
Patent
active
055140432
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns a transmission ratio change control method in a gear transmission device.
The present invention also concerns a device for implementing this method.
Transmission devices are known in which a direct drive ratio or a speed change ratio is achieved depending on whether two sets of teeth that mesh together are, respectively, stationary in relation to each other or in meshing motion in relation to each other.
In order to pass from one ratio to the other, one can, for example, squeeze or release a clutch which makes the two sets of teeth integral, directly or indirectly, to achieve the direct drive ratio, or, for example, brake one of the sets of teeth on a structure of the transmission device so that the other set of teeth rolls on the stationary one.
These clutch or brake controls, whether manual or automatic, may operate more or less abruptly depending on the circumstances. They require a work of friction which generates heat and wear.
FR-A-1 191 526 or U.S. Pat. No. 3,103,607, disclose transmission devices in which such changes are made by releasing or not releasing the delivery of at least one additional gear pump, whose impeller is connected to a rotating element of the combination of teeth, to release or not release this rotating element. But these arrangements are complex, heavy and cumbersome.
FR-2 190 220 describes a limited-slipping differential in which the combination of teeth transmits the power and is itself arranged to form an hydraulic pump whose outlet path becomes narrower as the relative speed of the teeth increases. It also has means which close off the outlet orifice when the oil temperature increases.
The aim of this invention is therefore to propose a method and a device in which the ratio changes may be made flexibly and with reduced wear, using simple means.
According to the invention, a ratio change control method is proposed in a transmission device comprising a combination of meshing sets of teeth capable of operating in a state of relative mobility in which the combination of teeth transmits power in a first transmission ratio between a transmission output and input, or in a state of relative fixity to achieve a second transmission ratio between the transmission output and input, the combination of meshing teeth taking the form of an hydraulic gear pump, a method whereby the second transmission ratio is controlled by substantially closing off the flow at the gear pump outlet, the first transmission ratio is controlled by releasing the flow at the gear pump outlet, and in order to pass from the first to the second ratio, after having at least partly closed off the flow at the gear pump outlet, a clutch is made to pass into the coupled state, said clutch tending in the coupled state to make the combination of teeth operate in the state of relative fixity and allowing in the uncoupled state the combination of teeth to assume the state of relative mobility corresponding to the first transmission ratio.
According to a second aspect of the invention, there is proposed a transmission device which has at least two ratios and comprises a combination of sets of teeth capable of operating in a state of relative mobility in which the combination transmits power in a first speed ratio between the transmission input and output, or in a state of relative fixity to achieve a second speed ratio between the transmission input and output, means for guiding oil through the regions of two sets of teeth in the combination which move towards each other during operation in he first transmission ratio, means for oil intake into the gaps between the teeth in at least one of these regions, an oil delivery path starting from a region where the two teeth start to mesh, ratio change control means for selectively opening or substantially closing off the oil delivery path to control the operation in the first transmission ratio or operation in the second transmission ratio respectively, and a clutch which selectively connects two rotating elements connected at least indirectly to the
REFERENCES:
patent: 1966979 (1934-07-01), Gardner
patent: 2133276 (1938-10-01), Ballantyne
patent: 2135917 (1938-11-01), Seybold
patent: 3130607 (1964-04-01), Kraemer
patent: 4322988 (1982-04-01), Hill
Antonov Automotive North America B.V.
Wright Dirk
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